1. Field of the Invention
This invention relates generally to extensible handles for use with tools. More particularly, the invention is directed to an extensible handle for applying different degrees of torque to a tool headpiece, such as a ratchet wrench, carried by the handle.
2. Description of the Prior Art
It is known to provide hand tools such as wrenches and the like with handles which may be temporarily extended for the purpose of increasing the effective leverage so that additional torque may be applied to the tool headpiece carried at the end of the handle. This is particularly advantageous when it is desired to provide extra pressure in tightening or loosening a threaded bolt or similar type of fastener.
Such tools with extensible handles usually include some provision for locking the extended portion of the handle in one or more desired positions of extension depending upon the amount of leverage and torque desired for a given application. This locking mechanism should desirably be easily manipulated and quickly engaged or disengaged so that the user of the tool will not be required to devote an inordinate amount of time or attention in adjusting for the desired degree of extension. Accordingly, such a tool handle should be capable of being quickly extended for a temporary period of special use and thereafter quickly retracted to its normal position for general use and storage.
Another desirable feature of an extensible tool handle is that the locking mechanism must be capable of securing the extensible portion of the handle in a very rigid and secure interconnecting relationship with the fixed portion of the handle so that the entire extended handle will properly function as a strong integral unit.
It is also further desirable to provide a locking mechanism which will function to maintain the extensible portion of the handle in its desired position notwithstanding the type of tool headpiece being utilized or the type of force being applied. For example, an extensible handle structure suitable for use in applying torque to a wrench headpiece should advantageously also be capable of supporting and applying torque to a tool headpiece such as a screwdriver or drill bit.
The prior art has indicated various approaches to providing an extensible handle for a handheld tool. For example, the use of a hollow sleeve having spaced internal threaded portions which may alternatively be screwed onto the fixed portion of the handle by reversing the position of the sleeve is known.
However, probably the most prevalent form of extensible handle construction involves the utilization of two elongated members that are telescopically retractable and extensible with respect to each other. The various positions of extension are maintained by some form of locking mechanism, such as a thrumbscrew or cooperating pin and groove assembly.
Specific examples of such prior art extensible handles are shown by the Jagielo U.S. Pat. No. 1,284,351; Mandle U.S. Pat. No. 2,282,148; and Blunt U.S. Pat. No. 2,964,981.